Analysis could help scientists determine whether quantum mechanics parameter varies with time

By Gabriel Popkin, 16:11 PM October 15, 2013

One of physics’ most fundamental constants just got a little more constant.

Physicists have placed the strictest limit yet on how much the fine structure constant — which determines how strongly electrically charged objects interact — could change with the density of nearby matter. The team's method for measuring the constant may help scientists probe whether the value has remained constant over the lifetime of the universe.

The fine structure constant, also known as alpha, has long been both e...